Category: Echinoderms

BOTH LITTLE KIDS AND MARINE BIOLOGISTS KNOW STARFISH BY THEIR FIVE ARMS. The starfish anatomy that lurks underneath a starfish’s bumpy skin is another thing (To be clear, the biologists know sea star facts, the rest of us not so much). There are 1,500 to 2,000 species of starfish, or sea stars, found in oceans worldwide, in pretty much every depth and type of habitat. They’re all alike in general architecture but come in a myriad

WITH FIVE ARMS STRETCHING IN FIVE DIRECTIONS, you’d think that starfish could move along the seafloor like Indiana Jones. In fact, usually they creep along on hundreds of little tube feet that line the undersides of those arms. But, researchers studying how starfish walk found something else: sometimes starfish bounce along for speed. As echinoderms in Class Asteroidea, starfish walk by operating their multitudes of little tiny feet through intricate networks of fluid-filled canals. With

A POST HERE SEVERAL MONTHS AGO closed with the “Really Odd Fact” that blenny-like pearlfish (Periclimenes imperator) have a habit of taking up residence in the … well…rear ends of sea cucumbers. The overall post, “Sea Cucumbers – Superheroes of the Sea,” was about the fact that sea cucumbers, often ignored as inert, unimportant creatures, actually had a lot to recommend them. THE PEARLFISH/CUCUMBER EQUATION The pearlfish/cuke interaction is generally described as commensal relationship, but that term implies a

THE (NEARLY IMMORTAL) LIVES OF SEA URCHINS IS THE FOCUS of this terrific video from the terrific folks at PBS’s Deep Look. Like most marine denizens, they endure long – and perilous – journeys as tiny larvae before settling into on some suitable substrate for a life eating algae. Once they transform into adults, they’re pretty much invulnerable, says Deep Look, with life expectancy as long at 200 years. The transformation process is amazing.

I’M NOT SURE WHETHER THIS IS FASCINATING OR CREEPY, but it does give us an idea of how sea stars and other echinoderms move along on little, hydraulically-operated tube feet. Apparently the poor guy got stranded on the sand as the tide went out. The videographer, Zeb Hallock, notes that after shooting the video, he put it and other sea stars back in the water.

TO MOST DIVERS, SEA CUCUMBERS WOULD SEEM LIKE THE INACTION FIGURES of the oceans. Mainly, they come off as inert, sausage-shaped lumps lying randomly on the sandy bottom and perhaps the least interesting objects on the reef. It’s time for real sea cucumber facts. Actually, some of them have real Captain Echinoderm moves in them. For one thing, they’re nocturnal so what you see in the daytime isn’t what you’d get at night, when they

THE MARKINGS OF THE FISHES AT LEFT AND LOWER RIGHT suggest members of the genus Canthigaster, sharp-nosed puffers often known as toby’s that are found in the Indo-Pacific. But the specific designs and colors are sufficiently different from the familiar black saddled toby (Canthigaster valentini) to suggest they’re not described in any of the references I have access to. CANTHIGASTER POSEIDONSWEBUS But there are a lot of fishes in the sea, so to speak, and

BLOOD STARS (HENRICIA SANGUINOLENTA) ARE OFTEN DARK RED, SMALL AND TALKATIVE – well, this one looked like he ought to be, anyway. I always thought that if Pixar made a film featuring this blood star, it should be played by Billy Crystal. I digress. They’re found from the far northern Atlantic to as far south as Cape Hatteras. The book says they’re as big as four inches across. All those I’ve seen, in New England, are